Which activity poses a risk for DCS due to nitrogen coming out of solution?

Deep-sea diving poses a risk for Decompression Sickness (DCS) because it involves exposure to high pressures that increase the solubility of nitrogen in the body's tissues and blood. When a diver ascends too quickly after a deep dive, the reduction in pressure can cause nitrogen that has been absorbed into the body to come out of solution rapidly, forming bubbles. These bubbles can lead to a range of symptoms associated with DCS, such as joint pain, dizziness, and more severe conditions if not treated promptly.

In contrast, while high-altitude flying and mountain climbing can expose individuals to lower atmospheric pressures and the effects of altitude on the body, they are not directly associated with nitrogen coming out of solution in the way that deep-sea diving is. Scuba snorkeling, typically done at shallower depths and with shorter durations, carries less risk than deep-sea diving because the pressures involved do not lead to the same level of nitrogen saturation. Thus, deep-sea diving is uniquely associated with the conditions that can lead to DCS due to nitrogen release.